--- /dev/null
+/*
+ * comedi/drivers/ni_labpc_isadma.c
+ * ISA DMA support for National Instruments Lab-PC series boards and
+ * compatibles.
+ *
+ * Extracted from ni_labpc.c:
+ * Copyright (C) 2001-2003 Frank Mori Hess <fmhess@users.sourceforge.net>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/module.h>
+#include <linux/slab.h>
+
+#include "../comedidev.h"
+
+#include "comedi_isadma.h"
+#include "ni_labpc.h"
+#include "ni_labpc_regs.h"
+#include "ni_labpc_isadma.h"
+
+/* size in bytes of dma buffer */
+#define LABPC_ISADMA_BUFFER_SIZE 0xff00
+
+/* utility function that suggests a dma transfer size in bytes */
+static unsigned int labpc_suggest_transfer_size(struct comedi_device *dev,
+ struct comedi_subdevice *s,
+ unsigned int maxbytes)
+{
+ struct comedi_cmd *cmd = &s->async->cmd;
+ unsigned int sample_size = comedi_bytes_per_sample(s);
+ unsigned int size;
+ unsigned int freq;
+
+ if (cmd->convert_src == TRIG_TIMER)
+ freq = 1000000000 / cmd->convert_arg;
+ else
+ /* return some default value */
+ freq = 0xffffffff;
+
+ /* make buffer fill in no more than 1/3 second */
+ size = (freq / 3) * sample_size;
+
+ /* set a minimum and maximum size allowed */
+ if (size > maxbytes)
+ size = maxbytes;
+ else if (size < sample_size)
+ size = sample_size;
+
+ return size;
+}
+
+void labpc_setup_dma(struct comedi_device *dev, struct comedi_subdevice *s)
+{
+ struct labpc_private *devpriv = dev->private;
+ struct comedi_isadma_desc *desc = &devpriv->dma->desc[0];
+ struct comedi_cmd *cmd = &s->async->cmd;
+ unsigned int sample_size = comedi_bytes_per_sample(s);
+
+ /* set appropriate size of transfer */
+ desc->size = labpc_suggest_transfer_size(dev, s, desc->maxsize);
+ if (cmd->stop_src == TRIG_COUNT &&
+ devpriv->count * sample_size < desc->size)
+ desc->size = devpriv->count * sample_size;
+
+ comedi_isadma_program(desc);
+
+ /* set CMD3 bits for caller to enable DMA and interrupt */
+ devpriv->cmd3 |= (CMD3_DMAEN | CMD3_DMATCINTEN);
+}
+EXPORT_SYMBOL_GPL(labpc_setup_dma);
+
+void labpc_drain_dma(struct comedi_device *dev)
+{
+ struct labpc_private *devpriv = dev->private;
+ struct comedi_isadma_desc *desc = &devpriv->dma->desc[0];
+ struct comedi_subdevice *s = dev->read_subdev;
+ struct comedi_async *async = s->async;
+ struct comedi_cmd *cmd = &async->cmd;
+ unsigned int max_samples = comedi_bytes_to_samples(s, desc->size);
+ unsigned int residue;
+ unsigned int nsamples;
+ unsigned int leftover;
+
+ /*
+ * residue is the number of bytes left to be done on the dma
+ * transfer. It should always be zero at this point unless
+ * the stop_src is set to external triggering.
+ */
+ residue = comedi_isadma_disable(desc->chan);
+
+ /*
+ * Figure out how many samples to read for this transfer and
+ * how many will be stored for next time.
+ */
+ nsamples = max_samples - comedi_bytes_to_samples(s, residue);
+ if (cmd->stop_src == TRIG_COUNT) {
+ if (devpriv->count <= nsamples) {
+ nsamples = devpriv->count;
+ leftover = 0;
+ } else {
+ leftover = devpriv->count - nsamples;
+ if (leftover > max_samples)
+ leftover = max_samples;
+ }
+ devpriv->count -= nsamples;
+ } else {
+ leftover = max_samples;
+ }
+ desc->size = comedi_samples_to_bytes(s, leftover);
+
+ comedi_buf_write_samples(s, desc->virt_addr, nsamples);
+}
+EXPORT_SYMBOL_GPL(labpc_drain_dma);
+
+static void handle_isa_dma(struct comedi_device *dev)
+{
+ struct labpc_private *devpriv = dev->private;
+ struct comedi_isadma_desc *desc = &devpriv->dma->desc[0];
+
+ labpc_drain_dma(dev);
+
+ if (desc->size)
+ comedi_isadma_program(desc);
+
+ /* clear dma tc interrupt */
+ devpriv->write_byte(dev, 0x1, DMATC_CLEAR_REG);
+}
+
+void labpc_handle_dma_status(struct comedi_device *dev)
+{
+ const struct labpc_boardinfo *board = dev->board_ptr;
+ struct labpc_private *devpriv = dev->private;
+
+ /*
+ * if a dma terminal count of external stop trigger
+ * has occurred
+ */
+ if (devpriv->stat1 & STAT1_GATA0 ||
+ (board->is_labpc1200 && devpriv->stat2 & STAT2_OUTA1))
+ handle_isa_dma(dev);
+}
+EXPORT_SYMBOL_GPL(labpc_handle_dma_status);
+
+void labpc_init_dma_chan(struct comedi_device *dev, unsigned int dma_chan)
+{
+ struct labpc_private *devpriv = dev->private;
+
+ /* only DMA channels 3 and 1 are valid */
+ if (dma_chan != 1 && dma_chan != 3)
+ return;
+
+ /* DMA uses 1 buffer */
+ devpriv->dma = comedi_isadma_alloc(dev, 1, dma_chan, dma_chan,
+ LABPC_ISADMA_BUFFER_SIZE,
+ COMEDI_ISADMA_READ);
+}
+EXPORT_SYMBOL_GPL(labpc_init_dma_chan);
+
+void labpc_free_dma_chan(struct comedi_device *dev)
+{
+ struct labpc_private *devpriv = dev->private;
+
+ if (devpriv)
+ comedi_isadma_free(devpriv->dma);
+}
+EXPORT_SYMBOL_GPL(labpc_free_dma_chan);
+
+static int __init ni_labpc_isadma_init_module(void)
+{
+ return 0;
+}
+module_init(ni_labpc_isadma_init_module);
+
+static void __exit ni_labpc_isadma_cleanup_module(void)
+{
+}
+module_exit(ni_labpc_isadma_cleanup_module);
+
+MODULE_AUTHOR("Comedi http://www.comedi.org");
+MODULE_DESCRIPTION("Comedi NI Lab-PC ISA DMA support");
+MODULE_LICENSE("GPL");
Code Review / kvmfornfv.git / blobdiff